A NAND flash memory has widely spread as a memory device for mass data. At present, cost reduction or realization of a high capacity per bit has been advanced by miniaturizing a memory element.
However, to further miniaturize the flash memory, there are many problems to be solved, e.g., a short channel effect, inter-element interference, suppression of a variation of elements, and others. Therefore, as a new memory device which can substitute for a conventional floating gate type flash memory, a two-terminal nonvolatile resistance change element as typified by a resistive random access memory (ReRAM) has been developed. For example, a memory that uses amorphous silicon for a resistance change unit has a high switching probability but does not have excellent data retention characteristics.